Objective To evaluate the therapeutic effect of panretinal photocoagulation (PRP) in the treatment of ischemic central retinal vein occlusion (CRVO) at different stages. Methods From June 2011 to April 2014, all the patients with ischemic CRVO diagnosed in our department by visual function, slit-lamp biomicroscopy, funduscopy under dilated pupil and fluorescein angiography were recruited in this study. Before PRP, the cohort was divided into 2 groups according to the existence of iris neovascularization (INV), that is, group A (34 eyes without INV) and group B (7 eyes with INV). All patients received standard PRP treatment in a period of 2 to 3 weeks, and the additional laser treatments were given during the follow-up period based on the results of fundus fluorescein angiography (FFA) or clinical manifestations. They were followed up for 6 months to 3 years [(19.3±8.5) months]. The incidence of severe complications and the times of laser treatment were observed and compared between the 2 groups. Results There was no statistical difference in the term of age of onset between the 2 groups (P＞0.05). When PRP finished, the times of laser treatment and the total number of laser spots needed were significantly greater in group B than those in group A (P＜0.05). The incidence of neovascular glaucoma (NVG) was obviously higher in group B (P＜0.05), but there was no statistical difference in vitreous hemorrhage (VH) between the 2 groups (P＞0.05). No significant difference was found in the visual acuity before and after treatment in both groups (P＞0.05). Conclusion For ischemic CRVO, the incidence of severe complications is relatively low, and the times of laser treatment and the total number of laser spots are also less when PRP is performed before the occurrence of INV.